JP2006157329A - Projection video display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection video display apparatus for preventing wrong detection of a tilt angle by an acceleration sensor resulting from temporary application of vibration to the projection video display apparatus so as to avoid a person for appreciating a video image from being discomfort. <P>SOLUTION: The projection video display apparatus for projecting a video image through display devices 31, 32, 33 receiving light emitted from a light source 1 includes: acceleration sensors 56 for sensing an acceleration exerted to the projection video display apparatus in their lateral direction; a microcomputer 53 for calculating a tilt angle of the projection video display apparatus on the basis of a value detected by the acceleration sensors 56; and a trapezoidal distortion correction means for applying trapezoidal distortion correction to the video image on the basis of the tilt angle of the projection video display apparatus calculated by the microcomputer 53, and the microcomputer 53 calculates the tilt angle of the projection video display apparatus on the basis of the sensing value of a plurality of the acceleration sensors 56. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projection display apparatus such as a liquid crystal projector.

As this type of projection display device, the tilt of the projection display device is detected by an acceleration sensor, and the trapezoidal distortion of the image is corrected based on the tilt angle of the projection display device obtained by the acceleration sensor. Is known (see, for example, Patent Document 1).
JP 2001-186538 A

  However, even though a projection video display device is installed in a stable location and a video is being viewed, a pet such as a cat or dog temporarily installs the projection video display device or projection video display device. The detected value of the acceleration sensor may change greatly temporarily only by touching the table.

  In this case, there is a risk that it may be determined that the tilt angle of the projection display apparatus has changed even though the tilt angle of the projection display apparatus has not changed. Then, unnecessary trapezoidal distortion correction of the video is performed based on the detection value of the acceleration sensor that has changed greatly, and thus there is a problem that a person watching the video feels uncomfortable.

  Accordingly, the present invention has been made to solve such a problem, and prevents erroneous detection of the inclination angle of the acceleration sensor due to temporary vibration applied to the projection display apparatus and allows the user to view the image. It is an object of the present invention to provide a projection display apparatus that does not make a person feel uncomfortable.

  Means for solving the above-described problems include an acceleration sensor for detecting an acceleration acting in a lateral direction of the projection display apparatus in a projection display apparatus for projecting an image of light emitted from a light source via a display device; A microcomputer that calculates the tilt angle of the projection display apparatus from the detection value detected by the acceleration sensor, and a trapezoidal distortion correction unit that corrects the trapezoidal distortion of the image based on the tilt angle of the projection display apparatus calculated by the microcomputer The microcomputer calculates an inclination angle of the projection display device based on a plurality of detection values detected by the acceleration sensor.

  According to the configuration of the first aspect of the present invention, a pet such as a cat or a dog temporarily touches a stand on which the projection display apparatus or the projection display apparatus is installed, and then the projection display apparatus. It is judged that the tilt angle of the camera has changed, and it is possible to prevent the person watching the video from feeling uncomfortable by correcting the trapezoidal distortion of unnecessary video. Play.

  A projection display apparatus according to an embodiment of the present invention will be described in detail below with reference to FIGS.

  As shown in FIGS. 1 and 2, the projection display apparatus of the present embodiment shows a three-plate liquid crystal projector 30 as an example. In the main body case 41 of the liquid crystal projector 30, an optical system 42 from the light source 1 described later to the projection lens 16 is disposed.

  FIG. 2 shows an optical system 42 disposed in the main body case 41. The light emitting unit in the light source 1 is composed of an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like.

  The integrator lens 4 is composed of a pair of lens groups (fly eye lenses) 4a and 4b, and each lens portion guides light emitted from the light source 1 to the entire surfaces of liquid crystal light valves 31, 32, and 33 described later. Thus, the partial luminance unevenness existing in the light source 1 is averaged, and the light amount difference between the center of the screen and the peripheral portion is reduced. The light passing through the integrator lens 4 is guided to the first dichroic mirror 7 after passing through the polarization conversion device 5 and the condenser lens 6.

  The first dichroic mirror 7 transmits light in the red wavelength band and reflects light in the cyan (green + blue) wavelength band. The light in the red wavelength band that has passed through the first dichroic mirror 7 is reflected by the reflection mirror 8 to change the optical path. The red light reflected by the reflection mirror 8 is light-modulated by passing through a lens 9 and a transmissive liquid crystal light valve 31 for red light. The light in the cyan wavelength band reflected by the first dichroic mirror 7 is guided to the second dichroic mirror 10.

  The second dichroic mirror 10 transmits light in the blue wavelength band and reflects light in the green wavelength band. The light in the green wavelength band reflected by the second dichroic mirror 10 is guided to the transmissive liquid crystal light valve 32 for green light through the lens 11 and is modulated by being transmitted therethrough. The light in the blue wavelength band that has passed through the second dichroic mirror 10 is guided to the blue-light transmissive liquid crystal light valve 33 through the total reflection mirror 12, total reflection mirror 13, and lens 14, and is transmitted therethrough. It is optically modulated.

  Each of the liquid crystal light valves 31, 32, 33 includes a panel portion 31b, in which liquid crystal is sealed between an incident-side polarizing plate 31a, 32a, 33a and a pair of glass substrates (with pixel electrodes and alignment films formed). 32b and 33b and output side polarizing plates 31c, 32c and 33c.

  The modulated light (each color video light) modulated by passing through the liquid crystal light valves 31, 32, 33 is synthesized by the cross dichroic prism 15 to become color video light. The color image light is enlarged and projected by the projection lens 16 and displayed on a screen (not shown).

  The control of the liquid crystal projector 30 will be described in detail based on the signal processing block diagram shown in FIG. In FIG. 3, analog video signals from video, personal computers, and the like are input to an input terminal 50, and these video signals are converted from analog to digital video signals by an ADC circuit 51. This digitized video signal is sent to the video signal processing circuit 52. The video signal processing circuit 52 has a function of converting the angle of view of the video signal according to a command from the microcomputer 53 that is a CPU. The video signal supplied from the video processing signal circuit 52 is converted from digital to analog by the DAC circuit 54. The video signal supplied by the DAC circuit 54 displays the image on the liquid crystal panel drive 55 (liquid crystal panels 31, 32, 33). The image is projected with projection light by the light source 1 on the back of the liquid crystal panel of the liquid crystal panel drive 55 (the liquid crystal panels 31, 32, 33) to become a projected image. The projected image is projected onto a screen (not shown) through the projection lens 16 of the optical system 42 that can change the magnification. The output of the acceleration sensor 56 that detects the acceleration acting in the lateral direction of the liquid crystal projector 30 is input to the microcomputer 53.

A method of calculating the tilt angle of the liquid crystal projector 30 based on the output of the acceleration sensor 56 will be described in detail with reference to FIG. As shown in FIG. 4, when the liquid crystal projector 30 is inclined by the angle θ, the acceleration P that is detected by the acceleration sensor 56 in the lateral direction of the liquid crystal projector 30 is P = G × Sinθ, where G is the weight acceleration. Since G is defined as 1 here, the tilt angle can be calculated from θ = Sin ⁻¹ (P / G).

  The microcomputer 53 corrects the trapezoidal distortion of the video based on the calculated tilt angle θ of the liquid crystal projector 30. However, even though the liquid crystal projector 30 is installed in a stable place and the user views the video, a pet such as a cat or a dog temporarily touches the table on which the liquid crystal projector 30 or the liquid crystal projector 30 is installed. Only the detected value of the acceleration sensor 56 may temporarily change greatly.

  In this case, it may be determined that the tilt angle of the liquid crystal projector 30 has changed even though the tilt angle of the liquid crystal projector 30 has not changed. Then, unnecessary and inappropriate trapezoidal distortion correction of the image is performed based on the detection value of the acceleration sensor 56 that has changed greatly, and there is a problem that the person watching the image feels uncomfortable. It was.

  Therefore, in the embodiment of the present invention, the above-described problems are solved by performing the control described in detail below. The solution will be described in detail based on the flowchart shown in FIG.

  When the installation of the liquid crystal projector 30 is completed and the power is turned on, the acceleration acting in the lateral direction of the liquid crystal projector 30 is detected by the acceleration sensor 56, and a plurality of detected values are acquired (step 1). In the embodiment of the present invention, the number of detection values acquired by the acceleration sensor 56 is 100. From the acquired 100 data, the maximum two data and the minimum two data are deleted, and the remaining 96 data are averaged to obtain angle data θ (step 2).

  In step 3, it is determined whether or not the previously calculated angle data θ ′ is present. If YES is determined in step 3, the difference between the angle data θ calculated in step 2 and the previously calculated angle data θ ′. Is compared with a predetermined value A (step 4). In step 4, the predetermined value A is set to 0.29. If the difference between the angle data θ and the angle data θ ′ is greater than or equal to the predetermined value A in step 4 (NO in S4), 1 is added to the count number L that makes the initial value 0 (step 5).

  Next, the count number L is compared with the predetermined number B (step 6). In step 6, the predetermined number of times B is set to 5. When the count number exceeds the predetermined number B in step 6 (YES in S6), that is, when the state in which the angle data θ has changed more than the predetermined value A occurs continuously for the predetermined number B or more, the finally calculated angle Based on the data θ, trapezoidal distortion correction is performed (step 7). Thereafter, the previously calculated θ ′ data is deleted, the θ ′ data is rewritten with the latest angle data θ (step 8), and the process returns to step 1.

  If NO is determined in step 3, that is, if it is in an initial state, the process proceeds to step 7 where trapezoidal distortion correction based on the angle data θ is performed. If YES is determined in step 4, the process proceeds to step 8 and the data of θ ′ is rewritten with the latest angle data θ. If NO is determined in step 6, the process returns to step 1.

  In this way, since the tilt angle of the liquid crystal projector 30 is calculated based on the detection values of the plurality of acceleration sensors 56, a pet such as a cat or dog temporarily installs the liquid crystal projector 30 or the liquid crystal projector 30. It is possible to prevent erroneous detection of the tilt angle of the liquid crystal projector 30 due to a temporary large change in the detection value of the acceleration sensor 56 just by touching the table.

  Further, only when it is determined as YES in Step 6, that is, when it is detected that the tilt angle of the liquid crystal projector 30 is continuously changed a predetermined number of times, the keystone distortion correction is performed. Even when data is dispersed or when vibration is temporarily transmitted to the liquid crystal projector 30 by mistake, it is possible to prevent a person watching the video from feeling uncomfortable.

  In the embodiment of the present invention, the maximum two pieces of data and the minimum two pieces of data are deleted from the plurality of detection value data detected by the acceleration sensor 56. However, the number of data to be deleted is four. It is not limited to. You may comprise so that the arbitrary number of data which fluctuated may be deleted.

  Further, the present invention is not limited to a method of deleting an arbitrary number of data from a plurality of data. For example, a method of deleting data that is not within ± 3 times the standard deviation with respect to the average value may be used.

  In the embodiment of the present invention, a liquid crystal projector using a liquid crystal display panel is shown. However, the present invention can also be applied to a projection image display apparatus having another image light generation system. In addition to the front projection type, the present invention can be applied to a rear projection type image display device. The present invention can also be applied to a projector of a DLP (Digital Light Processing) (registered trademark of Texas Instruments (TI)) system.

1 is an external perspective view of a liquid crystal projector according to an embodiment of the present invention. It is the block diagram which showed the optical system of the liquid crystal projector. It is the block diagram which showed the signal processing system of the liquid crystal projector. It is a side view which shows the inclination angle of the liquid crystal projector. It is a flowchart which shows the calculation method of the inclination angle of the liquid crystal projector.

Explanation of symbols

1 Light source 31 Liquid crystal light valve (display device)
32 Liquid crystal light valve (display device)
33 Liquid crystal light valve (display device)
53 Microcomputer 56 Acceleration sensor

Claims (1)

In a projection display apparatus that projects an image of light emitted from a light source through a display device, an acceleration sensor that detects acceleration acting in the lateral direction of the projection display apparatus and a detection value detected by the acceleration sensor A microcomputer for calculating an inclination angle of the projection display apparatus; and a trapezoidal distortion correction unit for correcting a trapezoidal distortion of the image based on the inclination angle of the projection display apparatus calculated by the microcomputer. A projection-type image display apparatus that calculates an inclination angle of the projection-type image display apparatus based on a plurality of detection values detected by the.